Breech mechanism for firearms



Aug. 25, 1953 J. B. PETERS 2,649,300

BREECH MECHANISM FOR FIREARMS Filed Nov. 29, 1950 4 Sheets-Sheet 1 Zwrcwfwm Aug. 1953 v J. B. PETERS 2,649,800 I BREECH MECHANISM FOR FIREARMS Filed Nov. 29, 1950 1 4 SheetsSheet 2 Aug. 25, 1953 PETERS 2,649,800

BREECH MECHANISM FOR FIREARMS Filed Nov. 29, 1950 4 Sheets-Sheet 5 We 73- WWY. I 1&9 "/M 2 1953' J. B. PETERS 2,649,800

BREECH MECHANISM FOR FIREARMS Filed Nov. 29, 1950 4 Sheets-Sheet 4 IN V EN TOR.

Patented Aug. 25, 1953 BREECH MECHANISM FOR FIREARMS James B. Peters, Lynn, Mass.

Application November 29, 1950, Serial No. 198,193

6 Claims.

This invention relates to breech mechanism for firearms and in particular comprises an improved breech mechanism of the bolt-action type which can be locked, unlocked, opened and closed solely by rectilinear motion of the bolt handle.

Heretofore breech mechanisms having sufficient strength and durability to withstand the pressures and shocks of the heavier loads, such as the 30-06 caliber, have consisted of the bolt action type of which the Mauser and Springfield actions are examples. Both actions are characterized by a bolt handle which must be raised to unlock the breech block, or bolt, and withdrawn to open the breech. This characteristic has been undesirable not only because of the dual motion involved, but also because the handle is above the receiver when the bolt is unlocked and thereby it limits the mounting of the sights, particularly telescope sights which are frequently mounted on the receiver directly above the bolt and handle.

My invention provides a breech mechanism having the inherent strength of the bolt action, but which is operable solely by rectilinear motion of the handle. Furthermore the handle may be situated on the side of the receiver and, because its motion is rectilinear, a telescopic sight may be mounted directly above the receiver without interfering with the loading and unloading operations of the bolt.

The breech mechanism of this invention consists of a receiver which carries a bolt mounted for longitudinal rectilinear motion. The bolt is provided with a lug that is movable transversely and may be so movable either with or independently of the bolt.

The internal surface of the receiver is provided with a configuration adapted to receive the lug and permit, separately and mutually exclusively, rectilinear longitudinal motion and transverse motion of the lug. The transverse motion is permitted at the forward end of the sweep of the longitudinal motion when the bolt which carries the lug is at its forwardmost position and provides a means for locking the bolt. In preferred embodiments of this invention the internal configuration of the receiver presents a longitudinal guide channel and an angularly displaced locking recess defining a locking shoulder, the locking recess being at the forward end of the guide channel and communicating therewith. Transverse and longitudinal motions of the lug are imparted by an actuating member which is interposed between the bolt and the receiver and to which is fastened the bolt handle. The actuating member is provided with a pair of skew cam surfaces which operate against an intermediate portion of the lug and cause it to move either transversely or longitudinally depending upon its instantaneous location in the recessed areas or channels of the receiver.

These and other features and advantages will best be understood from the following description of a preferred embodiment of my invention, selected for purposes of illustration and not by way of limitation, and shown in the accompanying drawings in which:

Fig. 1 is a view in perspective of the breech mechanism,

Fig. 2 is a view in elevation of the breech mechanism showing portions broken away to reveal the relationship of the various parts when the breech is open,

Fig. 3 is a View in elevation showing the various parts of the breech mechanism in exploded relation,

Fig. 4 is a view in elevation of the breech mechanism showing portions broken away to reveal the relationship of the various parts when the breech is locked,

Fig. 5 is a view in cross section taken along the line 5-5 of Fig. 2,

Fig. 6 is a view in cross section taken along the line 66 of Fig. 4,

Fig. 7 is a plan view of the forward portion of the breech mechanism, and

Fig. 8 is a view in elevation of a section taken along the line 8-8 of Fig. 7.

The receiver i shown in all the figures is conveniently a cylindrical housing, having an interior bore 2, shown in Fig. 3, axially aligned with the bore of the barrel (not shown)" which is secured to the forward end of the breech mechanism. The forward region 3 of said bore 2- is preferably of less diameter than the rearward region and containssecured therein a platform 6 shown in Figs. 7 and 8, the upper surface of which is flat forming in cross section a chord of the circular cross section of said bore. The bolt 5 is contained in the receiver 9 and fits snugly in the forward region 3 of the bore, the forward part of the'bolt being cut away to present a fiat-bottomed region 6 shown in Fig. 8 so that it will clear and cooperate with the platform Q as explained below. The bolt contains a firing pin 5a and actuating mechanism of conventional design (not shown in detail) and the receiver correspondingly carries a conventional trigger mechanism 1.

Mounted on the rearward portion of said bolt 5 is a collar 8 shown in Figs. 2 through 6 free to rotate but restrained as a longitudinal motion relative to the bolt. Conveniently said collar 8 fits over a necked down portion 9 of said bolt 5 and is secured thereon by a cap Ill which engages said bolt 5. The collar 8 carries a lu II which extends outwardly therefrom, said lug ll being provided with an intremediate section 12, the function and description of which appears below. The lug is received and freely movable in a recessed locking area and guide channel provided in the inner wall of the receiver I. Conveniently said recessed locking area and guide channel form an L-shaped channel, having a longitudinal leg or guide channel [3 and at the forward end thereof an arcuate transverse leg or looking channel 14. The locking recess or channel presents as its rear wall a locking shoulder I5 which engages the lug II in the locked position. Alternatively the locking area may consist simply in an abrupt enlargement of the bore of the receiver defining a transverse locking shoulder with which enlarged section the longitudinal guide channel I3 communicates. To facilitate assembly the guide channel extends rearwardly the length of the receiver.

The actuating member is preferably a sleeve 16 shown in Figs. 2 through 6 surrounding the bolt and collar and received in the annular space ll between the bolt 5 and receiver I. Skew cam surfaces are provided by a spiral slot IS in the actuating sleeve 15. The intermediate section 52 of the lug II is provided with corresponding rounded or spiral top and bottom surfaces, and extend through the spiral slot.

A forward portion of the spiral slot 18 surrounds the lug l I when it is received by the guide channel 13 of the receiver l and rearward portions cooperate with the lug II when it is received by the locking recess IA of the receiver I. The bottom portion of the actuating sleeve 95 is cut away so that the trigger mechanism 1 on the receiver can cooperate with the firing pin mechanism of the bolt as shown at l9 in Figs. 2 and 3.

The location of the lug H and collar 8 on the bolt should be such that in the closed position the lug is in the position of cooperation with the locking shoulder 15 provided by the locking channel M or other locking recess.

A longitudinal slot 20 is provided in the receiver, preferably on the side, as shown in Figs. 1, 5 and 6. A handle 2| extends through the longitudinal slot 20 and is fastened to the actuating sleeve [6. The entire assembly, including bolt, collar, lug, and sleeve are retained in the receiver by a cap screw 22 threaded into the rearmost end of said receiver. A stop block 23 is provided in the end of the longitudinal slot 2% and similarly retained by the cap screw 22, being held in the slot by a tongue-and-groove provided respectively in the stop block 23 and longitudinal slot 20.

The breech mechanism is assembled by first sliding the actuating sleeve 16 on the bolt 5 with the spiral slot [8 receiving the lug H, and positioning the two so that the lug ll lines up with the longitudinal guide channel l3 and the handle 2! on the sleeve l6 lines up with the longitudinal slot 28 as suggested by Fig. 3. The sleeve and bolt are then inserted into the receiver I, and the stop block 23 is placed in the longitudinal slot 20 and the cap screw 22 is threaded on the rear of the receiver.

It will easily be seen that forward motion of the handle 2| carries the bolt 5 forward so long i as the lug l I is received by the longitudinal guide channel l3. When the breech is closed by the bolt 5 forward motion of the bolt is prevented and continued forward motion of the handle 2] causes the actuating sleeve Hi to move longitudinally forward with respect to the bolt 5, and the lug II is caused by the reaction of the skew cam surfaces of the spiral slot I8 to rotate into the locking channel M where it engages the locking shoulder I5. Rearward motion of the handle in a similar fashion causes the lug to rotate out of locking position and to align with the guide channel. Thereafter continued rotation of the lug is prevented by a wall of the guide channel and continued rearward motion of the handle causes the bolt to be withdrawn.

During these operations the platform 4 in the forward end of the receiver l cooperates with the cutaway fiat bottomed forward end 6 of the bolt 5 to prevent rotation of the latter. These features and the collar 8 may be omitted, if desired, and the lug I I may then be fastened to the bolt itself, it being free to rotate. Such a modification of the structure would, of course, require obvious modifications of the firing mechanism which could be accomplished if desired by providing a free floating firing pin and a conventional hammer at the rear of the bolt, rather than the selfcontained spring loaded firing pin conventionally present in this type bolt.

Pig. 5 shows in cross section the position and cooperation of the elements when the lug is positioned for rectilinear motion and Fig. 6 shows in cross section the position and cooperation of the elements when the lug is locked.

It will be understood that, although I have described my invention in detail with respect to only one particular embodiment thereof, there are many modifications which suggest themselves to persons skilled in the art and which are accordingly part thereof. a

My invention provides a bolt type breech action having all the strength and durability inherent in such actions with the additional advantages that the handle or operating connection is operable by simple longitudinal rectilinear motion, and may be positioned to interfere with a minimum extent with the operation and equipping of a firearm.

Having thus disclosed my invention and described in detail a preferred embodiment thereof so that any person skilled in the art may practice it, I claim and desire to secure by Letters Patent:

1. In a firearm a breech mechanism comprising a receiver having an axial bore, a longitudinal guide channel in the internal surface of said receiver terminating at its forward end in a looking recess defining a locking shoulder in the internal surface of said receiver, a bolt mounted within said receiver for longitudinal motion therein, a lug longitudinally immovable with respect to said bolt mounted on said bolt for motion within said longitudinal groove and locking recess, and a bolt actuating member interposed and longitudinally movable between said bolt and said receiver, said bolt actuating member having opposed skew cam surfaces engaging said lug and operable thereagainst, whereby rectilinear longitudinal motion of said actuating member moves said lug within the longitudinal groove and locking, recess. 7

2. In a firearm a breech mechanism comprising a receiver having an axial bore, a longitudinal guide channel in the internal surface of said receiver terminating at its forward end in a locking recess defining a locking shoulder in the internal surface of said receiver, a bolt mounted within said receiver solely for longitudinal motion therein, a collar rotatably mounted on said bolt, a lug mounted on said collar for motion within said longitudinal groove and locking recess, and a bolt actuating member mounted solely for longitudinal motion between said collar and said receiver, said bolt actuating member having opposing skew cam surfaces engaging an intermediate portion of said lug and operable thereagainst, whereby rectilinear longitudinal motion of said actuating member moves the lug within the longitudinal groove and locking recess.

3. In a firearm a breech mechanism comprising a receiver, a cylindrical bolt mounted within said receiver for longitudinal motion, a lug mounted on said bolt rotationally movable with respect tosaid receiver, a longitudinal guide channel receiving said lug and permitting longitudinal motion thereof in said receiver when said bolt is open, a locking recess defining a locking shoulder receiving said lug and permitting rotational motion thereof in said receiver when said bolt is closed, said locking recess communicating with said guide channel at the forward end thereof, and a bolt actuating member mounted for longitudinal motion interposed between said bolt and said receiver, said bolt actuating member having opposing skew cam surfaces receiving be tween them an intermediate portion of said lug and operable thereagainst, whereby rectilinear longitudinal motion of said actuating member separately imparts rotational movement and rectilinear longitudinal movement to said lug within the confines of said guide channel and locking recess.

4. In a firearm a breech mechanism comprising a receiver, a cylindrical bolt mounted within said receiver solely for longitudinal motion, a collar rotatably mounted on said bolt and longitudinally fixed on said bolt, a lug mounted on said collar and extending outwardly therefrom, an L-shaped guide channel in said receiver receiving said lug and permitting longitudinal motion thereof in one leg of said channel and rotation thereof in the other leg of said channel, said latter leg being forward of said former leg, and a bolt actuating sleeve mounted solely for longitudinal motion interposed annularly between said bolt and said receiver, said bolt actuating sleeve having a spiral recess defining opposing spiral cam surfaces defining a channel receiving an intermediate portion of said lug and operable against the lug, whereby rectilinear longitudinal motion of said actuating sleeve separately imparts rotational movement and rectilinear longitudinal movement to said lug within the confines of said L-shaped guide channel.

5. In a firearm a breech mechanism comprising a receiver, a cylindrical bolt mounted within said receiver for longitudinal motion, a collar rotatably mounted on said bolt and longitudinally fixed on said bolt, a lug mounted on said collar and extending outwardly therefrom, an L-shaped guide channel in said receiver receiving said lug and permitting longitudinal motion thereof in one leg of said channel and rotation thereof in the other leg of said channel, said latter leg being forward of said former leg, and a bolt actuating sleeve mounted for longitudinal motion interposed annularly between said bolt and said receiver, said bolt actuating sleeve having a spiral recess defining opposing spiral cam surfaces receiving between them an intermediate portion of said lug and operable thereagainst, a longitudinal slot extending through said receiver and a handle attached to said sleeve and extending through said slot, whereby rectilinear motion of said handle imparts rectilinear motion to said actuating sleeve and thereby separately imparts rotation movement and rectilinear longitudinal movement to said lug within the confines of said L-shaped guide channel.

6. In a firearm breech mechanism comprising a receiver, a cylindrical bolt mounted in said receiver for longitudinal motion, a rotationally movable lug on said bolt, and an L-shaped guide channel in said receiver receiving said lug and permitting longitudinal motion thereof in one leg of said channel and rotation thereof in the other leg of said channel: a bolt actuating member comprising a sleeve adapted to be interposed annularly between said bolt and said receiver, said sleeve having a spiral recess defining opposing spiral cam surfaces adapted to receive an intermediate portion of said lug and operable thereagainst.

JAMES B. PETERS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,096,324 Stamm May 12, 1914 1,228,827 Saalfield June 5, 1917 1,323,065 Johnson Nov. 25, 1919 2,035,539 Dicke Mar. 31, 1936 2,297,693 Dicke Oct. 6, 1942 2,424,264 Yorks July 22 1947 

